The paper tray of this invention and the manner of active sheet feeding of this invention may be entirely conventional. It is also known to take information from a paper tray, such as paper size. Illustrative of this are U.S. Pat. No. 4,966,356 to Ohyabu et al in which grooves in a code identify the sheets in the tray and U.S. Pat. No. 4,786,042 to Stemrole in which paper-size setting changes sensor setting to the printer.
This invention employs physical camming action by the tray. U.S. Pat. No. 4,307,878 to Kono employs a camming action to adjust upward force to paper size, a function not done by this invention. U.S. Pat. No. 4,610,445 to Schneider et al employs a camming action to position a paper-lift mechanism.
This invention changes the nip force of feed rollers by control from the tray. Changing of nip force to free jams is conventional. U.S. Pat. No. 4,966,358 to Yokoi et al illustrates such moving of a press member against the biasing action of a spring. U.S. Pat. No. 5,103,261 to Matsao et al illustrates freeing paper when the lid is open.